Liquid crystal composition and liquid crystal display device

ABSTRACT

A liquid-crystal composition which satisfies at least one of properties including a high upper-limit temperature for the nematic phase, low lower-limit temperature for the nematic phase, low viscosity, high optical anisotropy, negatively high permittivity anisotropy, high specific resistance, high stability to ultraviolet, and high stability to heat or has a proper balance between at least two of those properties. The liquid-crystal composition comprises a first ingredient comprising at least one compound selected among compounds represented by the formulae (1-1) and (1-2) and a second ingredient comprising at least one compound selected among compounds represented by the formula (2) and has negative permittivity anisotropy. For example, R 1 , R 2 , R 3 , and R 4  each is C 1-12  alkyl; Z 1 , Z 2 , and Z 3  each is a single bond or —(CH 2 ) 2 —; and ring A is 1,4-cyclohexylene or 1,4-phenylene.

TECHNICAL FIELD

The present invention relates to a liquid crystal composition suitablefor use in an active matrix (AM) device, and an AM device containing thecomposition. More specifically, the invention relates to a liquidcrystal composition having a negative dielectric anisotropy, and alsorelates to a device of an in-plane switching (IPS) mode or a verticalalignment (VA) mode containing the composition.

BACKGROUND ART

In a liquid crystal display device, classification based on an operatingmode of liquid crystals includes phase change (PC), twisted nematic(TN), super twisted nematic (STN), electrically controlled birefringence(ECB), optically compensated bend (OCB), in-plane switching (IPS),vertical alignment (VA), and so forth. Classification based on a drivingmode of the device includes a passive matrix (PM) and an active matrix(AM). PM is further classified into static, multiplex and so forth, andAM is classified into a thin film transistor (TFT), a metal insulatormetal (MIM) and so forth. TFT is further classified into amorphoussilicon and polycrystal silicon. The latter is classified into a hightemperature type and a low temperature type according to a productionprocess. Classification based on a light source includes a reflectiontype utilizing a natural light, a transmission type utilizing abacklight and a semi-transmission type utilizing both the natural lightand the backlight.

These devices contain a liquid crystal composition having suitablecharacteristics. The liquid crystal composition has a nematic phase.General characteristics of the composition should be improved to obtainan AM device having good general characteristics. Table 1 belowsummarizes a relationship between the general characteristics of thetwo. The general characteristics of the composition will be explainedfurther based on a commercially available AM device. A temperature rangeof a nematic phase relates to the temperature range in which the devicecan be used. A desirable maximum temperature of the nematic phase is 70°C. or more and a desirable minimum temperature is −10° C. or less. Theviscosity of the composition relates to the response time of the device.A short response time is desirable for displaying a moving image withthe device. Accordingly, a small viscosity of the composition isdesirable. A small viscosity at a low temperature is more desirable.

TABLE 1 General Characteristics of Liquid Crystal Composition and AMDevice General Characteristics of General Characteristics of No aComposition an AM Device 1 Temperature range of a Usable temperaturerange is wide nematic phase is wide 2 Viscosity is small¹⁾ Response timeis short 3 Optical anisotropy is Contrast ratio is large suitable 4Absolute value of Threshold voltage is low, electric dielectricanisotropy is power consumption is small and large contrast ratio islarge 5 Specific resistance is Voltage holding ratio is large and largea contrast ratio is large 6 It is stable to ultraviolet Service life islong light and heat ¹⁾A liquid crystal composition can be injected intoa cell in a short time.

The optical anisotropy of the composition relates to the contrast ratioof the device. A device having a VA mode, an IPS mode or so forthutilizes electrically controlled birefringence. Accordingly, formaximizing the contrast ratio of a device having a VA mode, an IPS modeor so forth, a product (Δn·d) of the optical anisotropy (Δn) of thecomposition and the cell gap (d) of the device is designed to have aconstant value. Examples of the value include a range of from 0.30 μm to0.40 μm (for a VA mode) and a range of from 0.20 μm to 0.30 μm (for anIPS mode). Since the cell gap (d) is generally in a range of from 2 μmto 6 μm, the optical anisotropy of the composition is mainly in a rangeof from 0.05 to 0.16. A large dielectric anisotropy of the compositioncontributes to a low threshold voltage, a small electric powerconsumption and a large contrast ratio of the device. Accordingly, alarge dielectric anisotropy is desirable. A large specific resistance ofthe composition contributes to a large voltage holding ratio and a largecontrast ratio of the device. Accordingly, a composition having a largespecific resistance is desirable at room temperature and also at a hightemperature in the initial stage. A composition having a large specificresistance is desirable at room temperature and also at a hightemperature after it has been used for a long time. A stability of thecomposition to an ultraviolet light and heat relates to a service lifeof the liquid crystal display device. In the case where the stability ishigh, the device has a long service life. These characteristics aredesirable for an AM device used in a liquid crystal projector, a liquidcrystal television and so forth.

In an AM device having a TN mode, a composition having a positivedielectric anisotropy is used. In an AM device having a VA mode, acomposition having a negative dielectric anisotropy is used. In an AMdevice having an IPS mode, a composition having a positive or negativedielectric anisotropy is used. A liquid crystal composition having anegative dielectric anisotropy is disclosed in the following documents.

[Patent Document 1] JP 2004-532344 A/2004 [Patent Document 2] JP2002-201474 A/2002 [Patent Document 3] JP 2001-354967 A/2001 [PatentDocument 4] JP 2000-038585 A/2000 [Patent Document 5] JP H11-240890A/1999 [Patent Document 6] JP 2002-069449 A/2002 [Patent Document 7] JP2000-053602 A/2000 [Patent Document 8] JP 2001-262145 A/2001 [PatentDocument 9] JP 2001-115161 A/2001 [Patent Document 10] JP 2001-031972A/2001 [Patent Document 11] JP 2001-019965 A/2001

A desirable AM device is characterized as having a usable temperaturerange that is wide, a response time that is short, a contrast ratio thatis large, a threshold voltage that is low, a voltage holding ratio thatis large, a service life that is long, and so forth. Even onemillisecond shorter response time is desirable. Thus, the compositionhaving characteristics such as a high maximum temperature of a nematicphase, a low minimum temperature of a nematic phase, a small viscosity,a large optical anisotropy, a large negative dielectric anisotropy, alarge specific resistance, a high stability to an ultraviolet light, ahigh stability to heat, and so forth is especially desirable.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

An object of the invention is to provide a liquid crystal compositionthat satisfies many characteristics among the characteristics such as ahigh maximum temperature of a nematic phase, a low minimum temperatureof a nematic phase, a small viscosity, a large optical anisotropy, alarge negative dielectric anisotropy, a large specific resistance, ahigh stability to ultraviolet light and a high stability to heat.Another object of the invention is to provide a liquid crystalcomposition that is properly balanced regarding many characteristics.Still another object of the invention is to provide a liquid crystaldisplay device that contains the liquid crystal composition. A furtherobject of the invention is to provide a liquid crystal composition thathas a large optical anisotropy, a large negative dielectric anisotropy,a high stability to ultraviolet light and so forth, and is to provide anAM device that has a short response time, a large voltage holding ratio,a large contrast ratio, a long service life and so forth.

Means for Solving the Problems

The invention concerns a liquid crystal composition having a negativedielectric anisotropy that includes a first component containing atleast one compound selected from the group of compounds represented byformulas (1-1) and (1-2), and a second component containing at least onecompound selected from the group of compounds represented by formula(2), and a liquid crystal display device that includes the liquidcrystal composition:

(In formulas (1-1), (1-2) and (2), R¹ is independently alkyl having 1 to12 carbons; R², R³ and R⁴ are each independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12carbons; Z¹, Z² and Z³ are each independently a single bond or —(CH₂)₂—;and ring A is 1,4-cyclohexylene or 1,4-phenylene.)

ADVANTAGES OF THE INVENTION

One of the advantages of the invention is to provide a liquid crystalcomposition that satisfies many characteristics among thecharacteristics such as a high maximum temperature of a nematic phase, alow minimum temperature of a nematic phase, a small viscosity, a largeoptical anisotropy, a large negative dielectric anisotropy, a largespecific resistance, a high stability to ultraviolet light and a highstability to heat. Another of the advantages of the invention is toprovide a liquid crystal composition that is properly balanced regardingmany characteristics. Another of the advantages of the invention is toprovide a liquid crystal display device that contains the liquid crystalcomposition. One aspect of the invention is to provide a liquid crystalcomposition that has a large optical anisotropy, a large negativedielectric anisotropy, a high stability to ultraviolet light and soforth, and is to provide an AM device that has a short response time, alarge voltage holding ratio, a large contrast ratio, a long service lifeand so forth.

BEST MODE FOR CARRYING OUT THE INVENTION

The terms used in the specification and claims are defined as follows.The liquid crystal composition and/or the liquid crystal display deviceof the invention may occasionally be expressed simply as “thecomposition” or “the device,” respectively. A liquid crystal displaydevice is a generic term for a liquid crystal display panel and a liquidcrystal display module. The “liquid crystal compound” is a generic termfor a compound having a liquid crystal phase such as a nematic phase, asmectic phase and so forth, and also for a compound having no liquidcrystal phase but being useful as a component of a composition. Theuseful compound contains, for example, a 6-membered ring such as1,4-cyclohexylene and 1,4-phenylene, and a rod like molecular structure.An optically active compound may occasionally be added to thecomposition. Even in the case where the compound is a liquid crystalcompound, the compound is classified into an additive. At least onecompound selected from a group of compounds represented by formula (1-1)may be abbreviated to “the compound (1-1).” The “compound (1-1)” meansone compound or two or more compounds represented by formula (1-1). Theother formulas are applied with the same rules.

A higher limit of a temperature range of a nematic phase may beabbreviated to “a maximum temperature.” A lower limit of a temperaturerange of a nematic phase may be abbreviated to “a minimum temperature.”“A specific resistance is large” means that the composition has a largespecific resistance at room temperature and also at a high temperaturein the initial stage, the composition has a large specific resistance atroom temperature and also at a high temperature even after it has beenused for a long time. “A voltage holding ratio is large” means that adevice has a large voltage holding ratio at room temperature and also ata high temperature in the initial stage, the device has a large voltageholding ratio at room temperature and also at a high temperature evenafter it has been used for a long time. In the description of thecharacteristics such as optical anisotropy, the characteristics of thecomposition such as the optical anisotropy and so forth are valuesmeasured in the methods disclosed in Examples. The first componentincludes one compound or two or more compounds. “A ratio of the firstcomponent” means the percentage by weight (% by weight) of the firstcomponent based on the total weight of liquid crystal composition. Aratio of the second component and so forth are applied with the samerule. A ratio of an additive mixed with the composition means thepercentage by weight (% by weight) based on the total weight of liquidcrystal composition.

In the chemical formulas of the component compounds, symbol R¹ is usedin plural compounds. In these compounds, plural R¹ may be the same as ordifferent from each other. In one case, for example, R¹ of the compound(1) is ethyl and R¹ of the compound (2) is ethyl. In another case, R¹ ofthe compound (1) is ethyl and R¹ of the compound (2) is propyl. Thisrule is also applicable to the symbols R², R³ and so forth.

[1] A liquid crystal composition having a negative dielectric anisotropycomprising a first component comprising at least one compound selectedfrom the group of compounds represented by formulas (1-1) and (1-2), anda second component comprising at least one compound selected from thegroup of compounds represented by formula (2):

(in formulas (1-1), (1-2) and (2), R¹ is independently alkyl having 1 to12 carbons; R², R³ and R⁴ are each independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12carbons; Z¹, Z² and Z³ are each independently a single bond or —(CH₂)₂—;and ring A is 1,4-cyclohexylene or 1,4-phenylene.)

[2] A liquid crystal composition having a negative dielectric anisotropycomprising a first component comprising at least one compound selectedfrom the group of compounds represented by formulas (1-1-1) and (1-2-1),and a second component comprising at least one compound selected fromthe group of compounds represented by formula (2-1):

(in formulas (1-1-1), (1-2-1) and (2-1), R¹ is independently alkylhaving 1 to 12 carbons; R², R³ and R⁴ are each independently alkylhaving 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having2 to 12 carbons; and ring A is 1,4-cyclohexylene or 1,4-phenylene.)

[3] The liquid crystal composition according to item 1, wherein thefirst component is at least one compound selected from the group ofcompounds represented by formula (1-1), and the second component is atleast one compound selected from the group of compounds represented byformula (2).

[4] The liquid crystal composition according to item 1, wherein thefirst component is at least one compound selected from the group ofcompounds represented by formula (1-2), and the second component is atleast one compound selected from the group of compounds represented byformula (2).

[5] The liquid crystal composition according to any one of items 1 to 4,wherein a ratio of the first component is from 30% by weight to 80% byweight, and a ratio of the second component is from 20% by weight to 70%by weight, based on the total weight of the liquid crystal composition.

[6] The liquid crystal composition according to any one of items 1 to 5,wherein the composition further comprises, in addition to the firstcomponent and the second component, at least one compound selected fromthe group of compounds represented by formula (3) as a third component:

(in formula (3), R⁵ and R⁶ are each independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12carbons; Ring B, ring C, ring D and ring E are each independently1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or3-fluoro-1,4-phenylene; Z⁴ and Z⁵ are each independently a single bond,—(CH₂)₂—, —CH₂O—, —OCH₂—, —COO— or —OCO—; and P is 0 or 1.)

[7] The liquid crystal composition according to item 6, wherein thethird component is at least one compound selected from the group ofcompounds represented by formulas (3-1) to (3-4):

(in formulas (3-1) to (3-4), R⁷ is independently alkyl having to 12carbons or alkenyl having 2 to 12 carbons; and R⁸ is independently alkylhaving 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having2 to 12 carbons.)

[8] The liquid crystal composition according to item 6, wherein thethird component is at least one compound selected from the group ofcompounds represented by formulas (3-5) to (3-7):

(in formulas (3-5) to (3-7), R⁷ is independently alkyl having 1 to 12carbons or alkenyl having 2 to 12 carbons; and R⁸ is independently alkylhaving 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having2 to 12 carbons.)

[9] The liquid crystal composition according to item 7, wherein thethird component is at least one compound selected from the group ofcompounds represented by formula (3-1).

[10] The liquid crystal composition according to item 8, wherein thethird component is at least one compound selected from the group ofcompounds represented by formulas (3-6) and (3-7).

[11] The liquid crystal composition according to any one of items 6 to10, wherein a ratio of the first component is from 30% by weight to 75%by weight, a ratio of the second component is from 20% by weight to 65%by weight, and a ratio of the third component is from 5% by weight to50% by weight, based on the total weight of the liquid crystalcomposition.

[12] The liquid crystal composition according to any one of items 1 to11, wherein the composition further comprises, in addition to the firstcomponent, the second component and the third component, at least onecompound selected from the group of compounds represented by formulas(4-1) to (4-4) as a fourth component:

(in formulas (4-1) to (4-4), R⁹ is independently alkyl having 1 to 12carbons; and R¹⁰ is independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons or alkenyl having 2 to 12 carbons.)

[13] The liquid crystal composition according to item 12, wherein thefirst component is at least one compound selected from the group ofcompounds represented by formulas (1-1-1) and (1-2-1), the secondcomponent is at least one compound selected from the group of compoundsrepresented by formula (2-1), the third component is at least onecompound selected from the group of compounds represented by formulas(3-1), (3-5) and (3-6), and the fourth component is at least onecompound selected from the group of compounds represented by formulas(4-1) to (4-3).

[14] The liquid crystal composition according to item 12, wherein aratio of the first component is from 30% by weight to 70% by weight, aratio of the second component is from 20% by weight to 60% by weight, aratio of the third component is from 5% by weight to 45% by weight, anda ratio of the fourth component is from 5% by weight to 45% by weight,based on the total weight of the liquid crystal composition.

[15] The liquid crystal composition according to any one of items 1 to14, wherein the composition has an optical anisotropy of from 0.07 to0.20.

[16] The liquid crystal composition according to any one of items 1 to15, wherein the composition has a dielectric anisotropy of from −5.0 to−2.0.

[17] A liquid crystal display device that includes the liquid crystalcomposition according to any one of items 1 to 16.

[18] The liquid crystal display device according to item 17, wherein theliquid crystal display device has an operation mode of a VA mode or anIPS mode, and has a driving mode of an active matrix mode.

The invention further includes: (1) the composition described above,wherein the composition further contains an optically active compound;(2) the composition described above, wherein the composition furthercontains an additive, such as an antioxidant, an ultraviolet lightabsorbent and/or an antifoaming agent; (3) an AM device containing thecomposition described above; (4) a device having an IPS or VA mode,containing the composition described above; (5) a device of atransmission type, containing the composition described above; (6) useof the composition described above as a composition having a nematicphase; and (7) use as an optically active composition by adding anoptically active compound to the composition described above.

The composition of the invention will be explained in the followingorder. First, the constitution of component compounds in the compositionwill be explained. Second, the main characteristics of the componentcompounds and the main effects of the compounds on the composition willbe explained. Third, desirable ratios of the component compounds and thebasis thereof will be explained. Fourth, a desirable embodiment of thecomponent compounds will be explained. Fifth, examples of the componentcompound will be shown. Sixth, additives that may be added to thecomposition will be explained. Seventh, the preparation methods of thecomponent compound will be explained. Lastly, use of the compositionwill be explained.

First, the constitution of component compounds in the composition willbe explained. The composition of the invention is classified into thecomposition A and the composition B. The composition A may furthercontain other compounds such as another liquid crystal compound, anadditive, an impurity, and so forth. This liquid crystal compound isdifferent from the compound (1-1), the compound (1-2), the compound (2),the compound (3), the compound (4-1), the compound (4-2), the compound(4-3) and the compound (4-4). Such a liquid crystal compound is mixedwith the composition for the purpose of adjusting the characteristics ofthe composition. Among the liquid crystal compounds, an amount of acyano compound is desirably small from the viewpoint of stability toheat or ultraviolet light. The amount of a cyano compound is moredesirably 0% by weight. The additive includes an optically activecompound, an antioxidant, an ultraviolet light absorbent, a coloringmatter, an antifoaming agent and so forth. The impurity is a compoundand so forth contaminated in the process such as the synthesis of acomponent compound and so forth.

The composition B essentially consists of the compounds selected fromthe compound (1-1), the compound (1-2), the compound (2), the compound(3), the compound (4-1), the compound (4-2), the compound (4-3) and thecompound (4-4). The term “essentially” means that the composition doesnot contain a liquid crystal compound which is different from thesecompounds. The term “essentially” also means that the composition mayfurther contain the additive, the impurity, and so forth. The componentsof the composition B are fewer than those of the composition A. Thecomposition B is preferable to the composition A from the viewpoint ofcosts. The composition A is preferable to the composition B, becausecharacteristics of the composition A can be further adjusted by mixingwith other liquid crystal compounds.

Second, the main characteristics of the component compounds and the maineffects of the compounds on the composition will be explained. The maincharacteristics of the component compounds are summarized in Tables 2-1and 2-2 on the basis of the effect of the invention. In Tables 2-1 and2-2, the symbol L represents large or high, the symbol M represents amiddle degree, and the symbol S represents small or low. The symbols L,M and S are classification based on qualitative comparison among thecomponent compounds.

TABLE 2-1 Characteristics of Compounds Compound (1-1) (1-2) (2) (3-1)(3-2) (3-3) (3-4) Maximum temperature S M S M M M M Viscosity S M S M MM M Optical anisotropy M M-L S M M L L Dielectric anisotropy¹⁾ M-L M-L SS S S S Specific resistance L L L L L L L ¹⁾A value of dielectricanisotropy is negative, and the symbols show magnitude of absolutevalues.

TABLE 2-2 Characteristics of Compounds Compound (3-5) (3-6) (3-7) (4-1)(4-2) (4-3) (4-4) Maximum M L L S M M M temperature Viscosity M M M SM-L M-L M-L Optical S M L M M-L L L anisotropy Dielectric S S S M-L M-LM-L¹⁾ M-L¹⁾ anisotropy¹⁾ Specific L L L L L L L resistance ¹⁾A value ofdielectric anisotropy is negative, and the symbols show magnitude ofabsolute values.

The main effects of the component compounds to the characteristics ofthe composition upon mixing the component compounds to the compositionare as follows. The compound (1-1) increases the absolute value of thedielectric anisotropy. The compound (1-2) increases the opticalanisotropy and increases the absolute value of the dielectricanisotropy. The compound (2) decreases the minimum temperature anddecreases the viscosity. The compounds (3-1) and (3-2) decrease theminimum temperature and decrease the viscosity. The compounds (3-3) and(3-4) decrease the minimum temperature and increase the opticalanisotropy. The compound (3-5) decreases the minimum temperature anddecreases the viscosity. The compounds (3-6) and (3-7) increase themaximum temperature and increase the optical anisotropy. The compounds(4-1) and (4-2) increase the absolute value of the dielectricanisotropy. The compounds (4-3) and (4-4) increase the opticalanisotropy and increase the absolute value of the dielectric anisotropy.

Third, desirable ratios of the component compounds and the basistherefor will be explained. A desirable ratio of the first component is30% by weight or more for increasing the absolute value of thedielectric anisotropy, and is 80% by weight or less for decreasing theminimum temperature. A more desirable ratio is from 30% by weight to 75%by weight. A particularly desirable ratio is from 30% by weight to 70%by weight.

A desirable ratio of the second component is 20% by weight or more fordecreasing the viscosity, and is 70% by weight or less for decreasingthe minimum temperature. A more desirable ratio is from 20% by weight to65% by weight. A particularly desirable ratio is from 20% by weight to60% by weight.

The third component is particularly suitable for preparing a compositionhaving a small viscosity. A desirable ratio of the third component isfrom 5% by weight to 50% by weight for the purpose. A more desirableratio is from 5% by weight to 45% by weight. A particularly desirableratio is from 10% by weight to 45% by weight.

The fourth component is particularly suitable for preparing acomposition having a large absolute value of a dielectric anisotropy. Adesirable ratio of the fourth component is from 5% by weight to 45% byweight for the purpose. A more desirable ratio is from 10% by weight to45% by weight. A particularly desirable ratio is from 15% by weight to45% by weight.

In the composition A, a desirable total ratio of the first component,the second component, the third component and the fourth component is70% by weight or more for providing favorable characteristics. A moredesirable total ratio is 90% by weight or more. The total ratio of thefour components in the composition B is 100% by weight.

Fourth, desirable embodiments of the component compounds will beexplained. R¹ and R⁹ are each alkyl having 1 to 12 carbons. R², R³, R⁴,R⁵, R⁶, R⁸ and R¹⁰ are each independently alkyl having 1 to 12 carbons,alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons.Desirable R³, R⁴, R⁵, R⁶ and R⁸ are each linear alkyl having 1 to 10carbons for increasing the stability to ultraviolet light and heat andso forth. Desirable R² and R¹⁰ are each linear alkoxy having 1 to 10carbons for increasing the absolute value of the dielectric anisotropy.R⁷ is alkyl having 1 to 12 carbons or alkenyl having 2 to 12 carbons.Desirable R⁷ is linear alkoxy having 1 to 10 carbons for increasing thestability to ultraviolet light and heat and so forth.

Desirable alkyl is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl,octyl. More desirable alkyl is ethyl, propyl, butyl, pentyl, or heptylfor decreasing a viscosity.

Desirable alkoxy is methoxy, ethoxy, propoxy, butoxy, pentyloxy,hexyloxy, or heptyloxy. More desirable alkoxy is methoxy or ethoxy fordecreasing a viscosity.

Desirable alkenyl is vinyl, 1-propenyl, 2-propenyl, 1-butenyl,2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl,1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, or 5-hexenyl. More desirablealkenyl is vinyl, 1-propenyl, 3-butenyl, or 3-pentenyl for decreasing aviscosity. A desirable configuration of —CH═CH— in these alkenylsdepends on the position of a double bond. Trans is desirable in thealkenyl such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl,3-pentenyl, and 3-hexenyl for decreasing the viscosity. Cis is desirablein the alkenyl such as 2-butenyl, 2-pentenyl and 2-hexenyl. In thesealkenyls, linear alkenyl is preferable to branched alkenyl.

Preferred examples of alkenyl in which arbitrary hydrogen is replaced byfluorine include 2,2-difluorovinyl, 3,3-difluoro-2-propenyl,4,4-difluoro-3-butenyl, 5,5-difluoro-4-pentenyl and6,6-difluoro-5-hexenyl. More preferred examples thereof include2,2-difluorovinyl and 4,4-difluoro-3-propenyl for decreasing theviscosity.

Ring A is 1,4-cyclohexylene or 1,4-phenylene. Desirable ring A is1,4-cyclohexylene for increasing the maximum temperature. As theconfiguration of 1,4-cyclohexylene, trans is preferred to cis forincreasing the maximum temperature.

Ring B, ring C, ring D and ring E are each independently1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or3-fluoro-1,4-phenylene. Desirable ring B, ring C and ring D are each1,4-cyclohexylene or 1,4-phenylene for increasing the maximumtemperature and decreasing the viscosity. As the configuration of1,4-cyclohexylene, trans is preferred to cis.

Z¹, Z² and Z³ are each independently a single bond or —(CH₂)₂—.Desirable Z¹, Z² and Z³ are each a single bond for decreasing theviscosity. Z⁴ and Z⁵ are each independently a single bond, —(CH₂)₂—,—CH₂O—, —OCH₂—, —COO— or —OCO—. Desirable Z⁴ and Z⁵ are each single bondfor decreasing the viscosity.

P is 0 or 1. Desirable P is 0 for decreasing the viscosity.

Fifth, examples of the component compounds will be shown. In thedesirable compounds described below, R¹¹ is alkyl having 1 to 12carbons. R¹² and R¹³ are each alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons or alkenyl having 2 to 12 carbons. R⁷, R⁸, R⁹ andR¹⁰ are described above. In these desirable compounds, trans ispreferable to cis for the configuration of 1,4-cyclohexylene forincreasing a maximum temperature.

Desirable compounds (1-1) are the compounds (1-1-1) and (1-1-2). A moredesirable compound (1-1) is the compound (1-1-1). Desirable compounds(1-2) are the compounds (1-2-1-1), (1-2-1-2) (1-2-2-1) and (1-2-2-2).More desirable compounds (1-2) are the compounds (1-2-1-1) and(1-2-1-2). Desirable compounds (3) are the compounds (3-1), (3-2),(3-3), (3-4), (3-5), (3-6) and (3-7). More desirable compounds (3) arethe compounds (3-1), (3-6) and (3-7).

Sixth, additives capable of being mixed with the composition will beexplained. The additives include an optically active compound, anantioxidant, an ultraviolet light absorbent, a coloring matter, anantifoaming agent and so forth. An optically active compound is mixed inthe composition for inducing a helical structure of liquid crystal toprovide a twist angle. Examples of the optically active compound includethe compounds (5-1) to (5-4) below. A desirable ratio of the opticallyactive compound is 5% by weight or less, and a more desirable ratiothereof ranges from 0.01% by weight to 2%.

An antioxidant is mixed with the composition in order to avoid adecrease in specific resistance caused by heating in the air, or tomaintain a large voltage holding ratio at room temperature and also at ahigh temperature even after the device has been used for a long time.

Preferred examples of the antioxidant include the compound (6), whereinn is an integer of from 1 to 9. In the compound (6), desirable n are 1,3, 5, 7, or 9. More desirable n are 1 or 7. When n is 1, the compound(6) has a large volatility, and is effective in preventing the decreaseof specific resistance caused by heating in the air. When n is 7, thecompound (6) has a small volatility, and is effective in maintaining alarge voltage holding ratio at room temperature and also at a hightemperature even after the device has been used for a long time. Adesirable ratio of the antioxidant is 50 ppm or more in order to obtainthe advantages thereof and is 600 ppm or less in order to prevent themaximum temperature from being decreased and to prevent the minimumtemperature from being increased. A more desirable ratio is from 100 ppmto 300 ppm.

Preferred examples of the ultraviolet light absorbent include abenzophenone derivative, a benzoate derivative and a triazolederivative. A light stabilizer having steric hindrance such as an amineis also desirable. A desirable ratio of the absorbent and the stabilizeris 50 ppm or more for obtaining the advantages thereof and is 10,000 ppmor less for preventing the maximum temperature from being decreased andpreventing the minimum temperature from being increased. A moredesirable ratio thereof ranges from 100 ppm to 10,000 ppm.

A dichroic dye such as an azo dye or an anthraquinone dye is mixed withthe composition to suit for a device of a guest host (GH) mode. Adesirable ratio of the dye ranges from 0.01% to 10%. An antifoamingagent such as dimethyl silicone oil or methylphenyl silicone oil ismixed with the composition for preventing foaming. A desirable ratio ofthe antifoaming agent is 1 ppm or more for obtaining the advantagesthereof and is 1,000 ppm or less for preventing display failure fromoccurring. A more desirable ratio thereof ranges from 1 ppm to 500 ppm.

Seventh, the preparation methods of the component compounds will beexplained. These compounds can be prepared by known methods. Thepreparation method will be exemplified below. The compounds (1-1) and(1-2) are prepared by the method disclosed in JP 2000-053602 A/2000. Thecompound (2-1) is prepared by the method disclosed in JP S59-070624A/1984. The compound (3-7) is prepared by the method disclosed in JPH2-237949 A/1990. The compounds (4-1) and (4-2) are prepared by themethod disclosed in JP H2-503441 A/1990. The compound (4-4) is preparedby the method disclosed in JP H2-501071 A/1990. The antioxidant iscommercially available. The compound (6), wherein n is 1, is available,for example, from Sigma-Aldrich, Inc. The compound (6), wherein n is 7,is prepared by the method disclosed in U.S. Pat. No. 3,660,505.

The compounds for which preparation methods were not described above canbe prepared according to the methods described in Organic Syntheses(John Wiley & Sons, Inc.), Organic Reactions (John Wiley & Sons, Inc.),Comprehensive Organic Synthesis (Pergamon Press), New ExperimentalChemistry Course (Shin Jikken Kagaku Kouza) (Maruzen, Inc.), and soforth. The composition is prepared according to known methods using thecompounds thus obtained. For example, the component compounds are mixedand dissolved in each other by heating.

Last, use of the composition will be explained. Most of the compositionshave a minimum temperature of −10° C. or less, a maximum temperature of70° C. or more, and an optical anisotropy of from 0.07 to 0.20. Thedevice containing the composition has a large voltage holding ratio. Thecomposition is suitable for an AM device. The composition is suitableespecially for an AM device of a transmission type. The compositionhaving an optical anisotropy of from 0.08 to 0.25 and further having anoptical anisotropy of from 0.10 to 0.30 may be prepared by controllingratios of the component compounds or by mixing other liquid crystalcompounds. The composition can be used as a composition having a nematicphase and as an optically active composition by adding an opticallyactive compound.

The composition can be used for an AM device. It can also be used for aPM device. The composition can also be used for an AM device and a PMdevice having a mode such as PC, TN, STN, ECB, OCB, IPS, VA, and soforth. It is desirable to use the composition for an AM device having anIPS or VA mode. These devices may be of a reflection type, atransmission type or a semi-transmission type. It is desirable to usethe composition for a device of a transmission type. It can be used foran amorphous silicon-TFT device or a polycrystal silicon-TFT device. Thecomposition is also usable for a nematic curvilinear aligned phase(NCAP) device prepared by microcapsulating the composition, and for apolymer dispersed (PD) device in which a three dimensional net-workpolymer is formed in the composition.

EXAMPLES

When a sample was a composition, it was measured as it was, and theobtained value is described here. When a sample was a compound, a samplefor measurement was prepared by mixing 15% by weight of the compound and85% by weight of mother liquid crystals. A value of characteristic ofthe compound was calculated by extrapolating from a value obtained bymeasurement. Namely: extrapolated value=(value measured forsample−0.85×value measured for mother liquid crystals)/0.15. When asmectic phase (or crystals) separated out at this ratio at 25° C., aratio of the compound and mother liquid crystals was changed step bystep in the order of (10% by weight/90% by weight), (5% by weight/95% byweight), (1% by weight/99% by weight), respectively. Values for amaximum temperature, optical anisotropy, viscosity, and dielectricanisotropy of the compound were obtained by the extrapolation.

The composition of the mother liquid crystals is as shown below. All thepercentages for the composition are percentage by weight.

Measurement of the characteristics was carried out according to thefollowing methods. Most methods are described in the Standard ofElectric Industries Association of Japan, EIAJ ED-2521 A or those withsome modifications.

Maximum Temperature of a Nematic Phase (NI; ° C.): A sample was placedon a hot plate in a melting point apparatus equipped with a polarizingmicroscope and was heated at the rate of 1° C. per minute. A temperaturewas measured when a part of the sample began to change from a nematicphase into an isotropic liquid. A higher limit of a temperature range ofa nematic phase may be abbreviated to “a maximum temperature.”

Minimum Temperature of a Nematic Phase (Tc; ° C.): A sample having anematic phase was put in a glass vial and then kept in a freezer attemperatures of 0° C., −10° C., −20° C., −30° C., and −40° C. for tendays, respectively, and a liquid crystal phase was observed. Forexample, when the sample remained in a nematic phase at −20° C. andchanged to crystals or a smectic phase at −30° C., Tc was expressed as≦−20° C. A lower limit of a temperature range of a nematic phase may beabbreviated to “a minimum temperature.”

Viscosity (η; measured at 20° C., mPa·s): A viscosity was measured bymeans of an E-type viscometer.

Optical Anisotropy (refractive index anisotropy; Δn; measured at 25°C.): Measurement was carried out with an Abbe refractometer mounting apolarizing plate on an ocular using a light at a wavelength of 589 nm.The surface of a main prism was rubbed in one direction, and then asample was dropped on the main prism. Refractive index (n∥) was measuredwhen the direction of a polarized light was parallel to that of therubbing. Refractive index (n⊥) was measured when the direction of apolarized light was perpendicular to that of the rubbing. A value ofoptical anisotropy was calculated from the equation: Δn=n∥−n⊥.

Dielectric Anisotropy (Δ∈; measured at 25° C.): A value of a dielectricanisotropy was calculated from the equation: Δ∈=∈∥−∈⊥. The values ofdielectric constant (∈∥ and ∈⊥) were measured in the following manner.

(1) Measurement of dielectric constant (∈∥): A solution ofoctadecyltriethoxysilane (0.16 mL) dissolved in ethanol (20 mL) wascoated on a glass substrate having been well cleaned. The glasssubstrate was rotated with a spinner and then heated to 150° C. for 1hour. A sample was charged in a VA device having a distance (cell gap)of 4 μm between two sheets of the glass substrates, and the device wassealed with an adhesive capable of being cured with ultraviolet light.Sine waves (0.5 V, 1 kHz) were applied to the device, and after lapsingtwo seconds, a dielectric constant (∈∥) in the major axis direction ofthe liquid crystal molecule was measured.

(2) Measurement of dielectric constant (∈⊥): Polyimide was coated on aglass substrate having been well cleaned. The glass substrate was baked,and the resulting orientation film was subjected to a rubbing treatment.A sample was charged in a TN device having a distance between two sheetsof the glass substrates of 9 μm and a twisted angle of 80°. Sine waves(0.5 V, 1 kHz) were applied to the device, and after lapsing twoseconds, a dielectric constant (∈⊥) in the minor axis direction of theliquid crystal molecule was measured.

Threshold Voltage (Vth; measured at 25° C.; V): Measurement was carriedout with LCD Evaluation System Model LCD-5100 made by Otsuka ElectronicsCo., Ltd. The light source was a halogen lamp. A sample was poured intoa VA device of a normally black mode, in which a cell gap between twoglass plates was 4 μm, and a rubbing direction was antiparallel, and thedevice was sealed with a UV curing adhesive. Voltage to be applied ontothe device (60 Hz, rectangular waves) was increased stepwise by 0.02 Vstarting from 0 V up to 20 V. During the stepwise increasing, the devicewas irradiated with light in a perpendicular direction, and an amount ofthe light passing through the device was measured. Voltage-transmissioncurve was prepared, in which a maximum amount of a light corresponded to100% transmittance, a minimum amount of a light corresponded to 0%transmittance. Threshold voltage is a value at 10% transmittance.

Voltage Holding Ratio (VHR-1; measured at 25° C.; %): A TN device usedfor measurement has a polyimide-alignment film and the cell gap betweentwo glass plates is 5 μm. A sample was poured into the device, and thenthe device was sealed with an adhesive which is polymerized by theirradiation of an ultraviolet light. The TN device was impressed andcharged with pulse voltage (60 microseconds at 5 V). Decreasing voltagewas measured for 16.7 milliseconds with High Speed Voltmeter and thearea A between a voltage curve and a horizontal axis in a unit cycle wasobtained. The area B was an area without decreasing. Voltage holdingratio is a percentage of the area A to the area B.

Voltage Holding Ratio (VHR-2; measured at 80° C.; %): A TN device usedfor measurement has a polyimide-alignment film and the cell gap betweentwo glass plates is 5 μm. A sample was poured into the device, and thenthe device was sealed with an adhesive which is polymerized by theirradiation of an ultraviolet light. The TN device was impressed andcharged with pulse voltage (60 microseconds at 5 V). Decreasing voltagewas measured for 16.7 milliseconds with High Speed Voltmeter and thearea A between a voltage curve and a horizontal axis in a unit cycle wasobtained. The area B was an area without decreasing. Voltage holdingratio is a percentage of the area A to the area B.

Voltage Holding Ratio (VHR-3; measured at 25° C.; %): A voltage holdingratio was measured after irradiating with ultraviolet light to evaluatestability to ultraviolet light. A composition having large VHR-3 has alarge stability to ultraviolet light. A TN device used for measurementhas a polyimide-alignment film and the cell gap is 5 μm. A sample waspoured into the device, and then the device was irradiated with lightfor 20 minutes. The light source was a superhigh voltage mercury lampUSH-500D (produced by Ushio, Inc.), and the distance between the deviceand the light source is 20 cm. In measurement of VHR-3, a decreasingvoltage is measured for 16.7 milliseconds. VHR-3 is desirably 90% ormore, and more desirably 95% or more.

Voltage Holding Ratio (VHR-4; measured at 25° C.; %): A voltage holdingratio was measured after heating an TN device having a sample pouredtherein in a constant-temperature bath at 80° C. for 500 hours toevaluate stability to heat. A composition having large VHR-4 has a largestability to heat. In measurement of VHR-4, a decreasing voltage ismeasured for 16.7 milliseconds.

Response Time (τ; measured at 25° C.; ms): Measurement was carried outwith LCD Evaluation System Model LCD-5100 made by Otsuka ElectronicsCo., Ltd. Light source is a halogen lamp. Low-pass filter was set at 5kHz. A sample was poured into a VA device of a normally black mode, inwhich a cell gap between two glass plates was 4 μm, and a rubbingdirection was antiparallel, and the device was sealed with a UV curingadhesive. Rectangle waves (60 Hz, 10 V, 0.5 seconds) were applied to thedevice. During application, the device was irradiated with light in aperpendicular direction, and an amount of the light passing through thedevice was measured. A maximum amount of a light corresponds to 100%transmittance, and a minimum amount of a light corresponds to 0%transmittance. Response time is a period of time required for the changein transmittance from 90% to 10% (fall time: ms).

Specific Resistance (ρ; measured at 25° C.; Ωcm): 1.0 mL of a sample wascharged in a vessel equipped with electrodes. A direct current voltageof 10 V was impressed to the vessel, and after lapsing 10 second fromthe impress of voltage, the direct electric current was measured. Thespecific resistance was calculated by the equation: (specificresistance)={(voltage)×(electric capacity of vessel)}/{(directcurrent)×(dielectric constant of vacuum)}.

Gas Chromatographic Analysis: A Gas Chromatograph Model GC-14B made byShimadzu was used for measurement. The carrier gas was helium (2milliliters per minute). An evaporator and a detector (FID) were set upat 280° C. and 300° C., respectively. Capillary column DB-1 (length 30meters, bore 0.32 millimeters, film thickness 0.25 micrometers,dimethylpolysiloxane as stationary phase, no polarity) made by AgilentTechnologies, Inc. was used for the separation of the componentcompound. After the column had been kept at 200° C. for 2 minutes, itwas further heated to 280° C. at the rate of 5° C. per minute. A samplewas prepared in an acetone solution (0.1% by weight), and 1 microliterof the solution was injected into the evaporator. The recorder used wasa Chromatopac Model C-R5A made by Shimadzu or its equivalent. Gaschromatogram obtained showed a retention time of a peak and a peak areacorresponding to the component compound.

Solvents for diluting the sample may also be chloroform, hexane, and soforth. The following capillary columns may also be used for separatingthe component compound: HP-1 made by Agilent Technologies Inc. (length30 meters, bore 0.32 millimeters, film thickness 0.25 micrometers),Rtx-1 made by Restek Corporation (length 30 meters, bore 0.32millimeters, film thickness 0.25 micrometers), and BP-1 made by SGEInternational Pty. Ltd. (length 30 meters, bore 0.32 millimeters, filmthickness 0.25 micrometers). In order to prevent compound peaks fromoverlapping, a capillary column CBP1-M50-025 (length 50 meters, bore0.25 millimeters, film thickness 0.25 micrometers) made by ShimadzuCorporation may be used.

The ratios of the liquid crystal compounds contained in the compositioncan also be calculated in the following manner. A liquid crystalcompound can be detected by gas chromatography. An area ratio of peakson a gas chromatogram corresponds to a ratio (molar number) of liquidcrystal compounds. In the case where the aforementioned capillarycolumns are used, correction coefficients of the liquid crystalcompounds can be regarded as 1. Accordingly, the ratio (% by weight) ofliquid crystal compounds is calculated from the area ratio of peaks.

The invention will be explained in detail by way of Examples. Theinvention is not limited by the Examples described below. The compoundsdescribed in the Comparative Examples and the Examples are expressed bythe symbols according to the definition in Table 3. In Table 3, theconfiguration of 1,4-cyclohexylene is trans. The parenthesized numbernext to the symbolized compounds in the Examples corresponds to thenumber of the desirable compound. The symbol (−) means other liquidcrystal compound. A ratio (percentage) of a liquid crystal compound ispercentage by weight (% by weight) based on the total weight of liquidcrystal compounds, and the liquid crystal compositions further containimpurities. Last, the characteristics of the composition are summarized.

TABLE 3 Method of Descriptbn of Compound using Symbols R—(A₁)—Z₁— . . .—Z_(n)—(A_(n))—R′ (1) Left Terminal Group R— Symbol C_(n)H_(2n+1)— n-C_(n)H_(2n+1)O— nO— C_(n)H_(2n+1)OC_(m)H_(2m)— nOm- CH₂═CH— V—CH₂═CHC_(n)H_(2n)— Vn- C_(m)H_(2m+1)CH═CH— mV—C_(m)H_(2m+1)CH═CHC_(n)H_(2n)— mVn- CF₂═CHC_(n)H_(2n)— VFFn- (2) Ringstructure —An— Symbol

B

B(2F)

B(3F)

B(2f, 3F)

H (3) Bonding Group —Zn— Symbol —C₂H₄— 2 —CH═CH— V —CH₂O— 1O —OCH₂— O1—COO— E —OCO— Er (4) Right Terminal Group —R′ Symbol —C_(n)H_(2n+1) -n—OC_(n)H_(2n+1) —On —CH═CH₂ —V —CH═CHC_(n)H_(2n+1) —Vn (5) Example ofDescription Example 1 1V2-HB(2F, 3F)-O2

Example 2 V—HHB-2

Example 3 2-HHEBH-1

Comparative Example 1

A composition corresponding to Example 4 was selected from thecompositions disclosed in JP 2004-532344 A/2004. The basis is that thecomposition contains the compound (2), the compound (3), the compound(4-1), the compound (4-2) and the compound (4-3), and contains acompound analogous to the compound (1-1) or (1-2). The components andcharacteristics of the composition were as follows.

3-HH-5 (2-1) 5% 3-HH-V1 (2-1) 9% 5-HH-V (2-1) 18% V2-HHB-1 (3-1) 8%5-HB(2F,3F)-O2 (4-1) 6% 5-HB(2F,3F)-O4 (4-1) 10% 3-HHB(2F,3F)-O2 (4-2)9% 2-HBB(2F,3F)-O2 (4-3) 8% 3-HBB(2F,3F)-O2 (4-3) 9% V-HB(2F,3F)-O2 (—)9% V-HB(2F,3F)-O4 (—) 9%NI=70.2° C.; Tc≦−40° C.; Δn=0.091; Δ∈=−3.4; Vth=2.10 V; η=19.6 mPa·s

Comparative Example 2

A composition corresponding to Example 12 was selected from thecompositions disclosed in JP 2001-354967 A/2001. The basis is that thecomposition contains the compound (2), the compound (3), the compound(4-1), the compound (4-2) and the compound (4-3), and contains acompound analogous to the compound (1-1) or (1-2). The components andcharacteristics of the composition were as follows.

3-HH-5 (2-1) 5% 3-HH-V1 (2-1) 10% 5-HH-V (2-1) 20% 3-HBB-2 (3-2) 3%3-HB(2F,3F)-O4 (4-1) 10% 5-HB(2F,3F)-O4 (4-1) 16% 3-HHB(2F,3F)-O2 (4-2)6% 2-HBB(2F,3F)-O2 (4-3) 10% 3-HBB(2F,3F)-O2 (4-3) 10% V-HBB(2F,3F)-O2(—) 10%NI=80.0° C.; Tc≦−30° C.; Δn=0.102; Δ∈=−3.5; Vth=2.17 V; η=22.7 mPa·s

Comparative Example 3

A composition corresponding to Example 11 was selected from thecompositions disclosed in JP 2000-053602 A/2000. The basis is that thecomposition contains the compound (2), the compound (4-1) and thecompound (4-3), and contains a compound analogous to the compound (1-1)or (1-2). The components and characteristics of the composition were asfollows.

2-HH-3 (2-1) 5% 3-HH-4 (2-1) 6% 3-HH-O1 (2-1) 4% 3-HH-O3 (2-1) 5%5-HH-O1 (2-1) 4% 3-HB(2F,3F)-O2 (4-1) 12% 5-HB(2F,3F)-O2 (4-1) 11%3-HHB(2F,3F)-O2 (4-2) 14% 5-HHB(2F,3F)-O2 (4-2) 15% V-HB(2F,3F)-O3 (—)8% V2-HB(2F,3F)-O2 (—) 8% V2-HHB(2F,3F)-O2 (—) 8%NI=71.7° C.; Δn=0.079; Δ∈=−4.4; η=26.0 mPa·s

Example 1

The composition of Example 1 has a high maximum temperature of a nematicphase, a large negative dielectric anisotropy and a small viscosity, ascompared to the composition of Comparative Example 1.

1V2-HB(2F,3F)-O2 (1-1-1) 10% 1V2-HB(2F,3F)-O4 (1-1-1) 10%1V2-H2B(2F,3F)-O2 (1-1-2) 10% 1V2-H2B(2F,3F)-O4 (1-1-2) 9%1V2-HHB(2F,3F)-O2 (1-2-1-1) 7% 1V2-HHB(2F,3F)-O4 (1-2-1-1) 8%1V2-HBB(2F,3F)-O2 (1-2-1-2) 6% 2-HH-5 (2-1) 10% 3-HH-4 (2-1) 15% 3-HH-5(2-1) 10% 3-HH-V1 (2-1) 5%NI=72.3° C.; Tc≦−20° C.; Δn=0.084; Δ∈=−3.6; Vth=2.06 V; η=17.7 mPa·s;VHR-1=99.1%; VHR-2=98.1%; VHR-3=97.9%

Example 2

The composition of Example 2 has a high maximum temperature of a nematicphase, a large negative dielectric anisotropy and a small viscosity, ascompared to the composition of Comparative Example 2.

1V2-HB(2F,3F)-O2 (1-1-1) 10% 1V2-HB(2F,3F)-O4 (1-1-1) 9%1V2-H2B(2F,3F)-O2 (1-1-2) 10% 1V2-H2B(2F,3F)-O4 (1-1-2) 9%1V2-HHB(2F,3F)-O2 (1-2-1-1) 7% 1V2-HHB(2F,3F)-O4 (1-2-1-1) 7%1V2-HBB(2F,3F)-O2 (1-2-1-2) 7% 3-HH-V (2-1) 10% 3-HH-V1 (2-1) 10%V-HHB-1 (3-1) 7% V2-HHB-1 (3-1) 6% 3-HB-O2 (—) 4% 5-HB-O2 (—) 4%NI=80.9° C.; Tc≦−20° C.; Δn=0.100; Δ∈=−3.6; Vth=2.14 V; η=18.8 mPa·s;VHR-1=99.0%; VHR-2=98.3%; VHR-3=98.1%

Example 3

The composition of Example 3 has a high maximum temperature of a nematicphase and a small viscosity, as compared to the composition ofComparative Example 3.

1V2-HB(2F,3F)-O2 (1-1-1) 10% 1V2-HB(2F,3F)-O3 (1-1-1) 9%1V2-HB(2F,3F)-O4 (1-1-1) 9% 1V2-H2B(2F,3F)-O2 (1-1-2) 10%1V2-H2B(2F,3F)-O4 (1-1-2) 9% 1V2-HHB(2F,3F)-O2 (1-2-1-1) 3%1V2-HH2B(2F,3F)-O2 (1-2-2-1) 7% 1V2-HH2B(2F,3F)-O4 (1-2-2-1) 6%1V2-HB2B(2F,3F)-O2 (1-2-2-2) 5% 1V2-HB2B(2F,3F)-O4 (1-2-2-2) 5% 2-HH-3(2-1) 11% 3-HH-V (2-1) 9% 3-HH-V1 (2-1) 7%NI=73.0° C.; Tc≦−20° C.; Δn=0.095; Δ∈=−4.4; Vth=1.87 V; η=18.8 mPa·s;VHR-1=98.9%; VHR-2=98.0%; VHR-3=97.7%

Example 4

1V2-HB(2F,3F)-O2 (1-1-1) 10% 1V2-HB(2F,3F)-O3 (1-1-1) 9%1V2-HB(2F,3F)-O4 (1-1-1) 9% 1V2-HHB(2F,3F)-O2 (1-2-1-1) 7%1V2-HHB(2F,3F)-O4 (1-2-1-1) 7% 1V2-HBB(2F,3F)-O2 (1-2-1-2) 7%1V2-HBB(2F,3F)-O4 (1-2-1-2) 7% 2-HH-3 (2-1) 11% 3-HH-4 (2-1) 15% 3-HH-5(2-1) 8% 5-HH-O1 (2-1) 5% 3-HB-O2 (—) 5%NI=75.4° C.; Tc≦−20° C.; Δn=0.090; Δ∈=−3.4; η=19.1 mPa·s

Example 5

1V2-HB(2F,3F)-O2 (1-1-1) 10% 1V2-H2B(2F,3F)-O2 (1-1-2) 10%1V2-HHB(2F,3F)-O2 (1-2-1-1) 6% 1V2-HHB(2F,3F)-O4 (1-2-1-1) 6%1V2-HBB(2F,3F)-O2 (1-2-1-2) 7% 1V2-HBB(2F,3F)-O4 (1-2-1-2) 7% 3-HH-V(2-1) 25% 3-HH-V1 (2-1) 9% 2-BB(3F)B-3 (3-3) 5% 3-HB(2F,3F)-O2 (4-1) 6%2-HBB(2F,3F)-O2 (4-3) 4% 3-HBB(2F,3F)-O2 (4-3) 5%NI=84.8° C.; Tc≦−20° C.; Δn=0.113; Δ∈=−3.4; η=18.9 mPa·s

Example 6

1V2-HB(2F,3F)-O2 (1-1-1) 10% 1V2-HB(2F,3F)-O3 (1-1-1) 10%1V2-HB(2F,3F)-O4 (1-1-1) 10% 1V2-H2B(2F,3F)-O2 (1-1-2) 10%1V2-HHB(2F,3F)-O2 (1-2-1-1) 6% 1V2-HHB(2F,3F)-O4 (1-2-1-1) 6%1V2-HBB(2F,3F)-O2 (1-2-1-2) 6% 2-HH-3 (2-1) 11% 3-HH-4 (2-1) 15% 3-HH-5(2-1) 10% 3-HHEH-4 (3-5) 3% 3-HHEH-5 (3-5) 3%NI=70.8° C.; Tc≦−20° C.; Δn=0.081; Δ∈=−3.4; η=19.0 mPa·s

Example 7

1V2-HB(2F,3F)-O2 (1-1-1) 14% 1V2-HB(2F,3F)-O3 (1-1-1) 14%1V2-HB(2F,3F)-O4 (1-1-1) 12% 1V2-HHB(2F,3F)-O2 (1-2-1-1) 3%1V2-HBB(2F,3F)-O4 (1-2-1-2) 7% 1V2-HBB(2F,3F)-1 (1-2-1-2) 7% 2-HH-3(2-1) 11% 3-HH-4 (2-1) 14% 3-HH-5 (2-1) 9% 3-HHB-1 (3-1) 3% 3-HHEBH-3(3-6) 3% 3-HHEBH-5 (3-6) 3%NI=79.0° C.; Tc≦−20° C.; Δn=0.085; Δ∈=−3.4; η=19.0 mPa·s

Example 8

1V2-HB(2F,3F)-O2 (1-1-1) 9% 1V2-HB(2F,3F)-O3 (1-1-1) 9% 1V2-HB(2F,3F)-O4(1-1-1) 9% 1V2-H2B(2F,3F)-O4 (1-1-2) 9% 1V2-HHB(2F,3F)-O2 (1-2-1-1) 6%1V2-HHB(2F,3F)-1 (1-2-1-1) 6% 1V2-HBB(2F,3F)-O2 (1-2-1-2) 6%1V2-HBB(2F,3F)-O4 (1-2-1-2) 6% 2-HH-3 (2-1) 11% 2-HH-5 (2-1) 4% 3-HH-4(2-1) 7% 3-HH-V (2-1) 8% 3-HH-V1 (2-1) 5% 5-HBB(3F)B-3 (3-7) 5%NI=78.5° C.; Tc≦−20° C.; Δn=0.097; Δ∈=−3.4; η=18.9 mPa·s

Example 9

1V2-HB(2F,3F)-O2 (1-1-1) 6% 1V2-HB(2F,3F)-O4 (1-1-1) 6%1V2-H2B(2F,3F)-O2 (1-1-2) 7% 1V2-H2B(2F,3F)-O4 (1-1-2) 6%1V2-HH2B(2F,3F)-O2 (1-2-2-1) 5% 1V2-HH2B(2F,3F)-O4 (1-2-2-1) 5%1V2-HB2B(2F,3F)-O2 (1-2-2-2) 5% 1V2-HB2B(2F,3F)-O4 (1-2-2-2) 5% 3-HH-V(2-1) 12% 3-HH-V1 (2-1) 10% 5-HH-V (2-1) 5% 2-BBB(2F)-3 (3-4) 5%2-BBB(2F)-5 (3-4) 5% 3-HB(2F,3F)-O2 (4-1) 8% 5-HB(2F,3F)-O2 (4-1) 7%2-BB(2F,3F)B-3 (4-4) 3%NI=74.5° C.; Tc≦−20° C.; Δn=0.112; Δ∈=−3.44; η=18.9 mPa·s

Example 10

1V2-HB(2F,3F)-O2 (1-1-1) 7% 1V2-HB(2F,3F)-O3 (1-1-1) 7% 1V2-HB(2F,3F)-O4(1-1-1) 6% 1V2-H2B(2F,3F)-O2 (1-1-2) 7% 1V2-H2B(2F,3F)-O4 (1-1-2) 7%1V2-HH2B(2F,3F)-O2 (1-2-2-1) 7% 1V2-HH2B(2F,3F)-O4 (1-2-2-1) 7%1V2-HB2B(2F,3F)-O2 (1-2-2-2) 7% 2-H2H-3 (2-2) 9% 3-H2H-V (2-2) 9%V-HHB-1 (3-1) 7% 2-BB(3F)B-3 (3-3) 5% 2-BB(3F)B-5 (3-3) 5% 3-HB-O1 (—)5% 5-HB-3 (—) 5%NI=71.0° C.; Tc≦−20° C.; Δn=0.109; Δ∈=−3.5; η=19.1 mPa·s

Example 11

1V2-HB(2F,3F)-O2 (1-1-1) 9% 1V2-HB(2F,3F)-O4 (1-1-1) 10% 3-HH-5 (2-1) 5%3-HH-V (2-1) 15% 3-HH-V1 (2-1) 10% V2-HHB-1 (3-1) 3% 3-HHB-O1 (3-1) 5%3-HB(2F,3F)-O2 (4-1) 10% 5-HB(2F,3F)-O2 (4-1) 10% 3-HHB(2F,3F)-O2 (4-2)10% 5-HHB(2F,3F)-O2 (4-2) 10% 2-HHB(2F,3F)-1 (4-2) 3%NI=72.6° C.; Tc≦−20° C.; Δn=0.079; Δ∈=−3.4; η=18.9 mPa·s

Example 12

1V2-HHB(2F,3F)-O2 (1-2-1-1) 5% 1V2-HHB(2F,3F)-O3 (1-2-1-1) 5%1V2-HHB(2F,3F)-O4 (1-2-1-1) 5% 1V2-HHB(2F,3F)-1 (1-2-1-1) 5%1V2-HBB(2F,3F)-O4 (1-2-1-2) 5% 1V2-HBB(2F,3F)-1 (1-2-1-2) 5%1V2-HH2B(2F,3F)-O2 (1-2-2-1) 5% 1V2-HH2B(2F,3F)-O4 (1-2-2-1) 5% 5-HH-O1(2-1) 10% 2-H2H-3 (2-2) 10% 3-H2H-V (2-2) 10% 3-HHB-O1 (3-1) 5%3-HB(2F,3F)-O2 (4-1) 5% 3-HB(2F,3F)-O4 (4-1) 5% 5-HB(2F,3F)-O4 (4-1) 5%3-HB-O1 (—) 7% 3-HB-O2 (—) 3%NI=81.2° C.; Tc≦−20° C.; Δn=0.088; Δ∈=−3.4; η=19.0 mPa·s

Example 13

1V2-HB(2F,3F)-O2 (1-1-1) 8% 1V2-HB(2F,3F)-O3 (1-1-1) 8% 1V2-HB(2F,3F)-O4(1-1-1) 8% 1V2-H2B(2F,3F)-O2 (1-1-2) 8% 1V2-HHB(2F,3F)-O2 (1-2-1-1) 6%1V2-HHB(2F,3F)-O3 (1-2-1-1) 6% 1V2-HBB(2F,3F)-O2 (1-2-1-2) 5% 3-HH-V(2-1) 24% 3-HH-V1 (2-1) 3% V-HHB-1 (3-1) 8% 5-HHB(2F,3F)-O2 (4-2) 5%3-HBB(2F,3F)-O2 (4-3) 5% 2-BB(2F,3F)B-3 (4-4) 3% 2-BB(2F,3F)B-4 (4-4) 3%NI=80.9° C.; Tc≦−20° C.; Δn=0.103; Δ∈=−3.4; η=18.9 mPa·s

Example 14

1V2-HB(2F,3F)-O2 (1-1-1) 9% 1V2-HB(2F,3F)-O4 (1-1-1) 8%1V2-HHB(2F,3F)-O2 (1-2-1-1) 5% 1V2-HBB(2F,3F)-O2 (1-2-1-2) 5%1V2-HH2B(2F,3F)-O2 (1-2-2-1) 8% 1V2-HH2B(2F,3F)-O4 (1-2-2-1) 7% 2-HH-3(2-1) 11% 3-HH-V (2-1) 10% 3-HH-V1 (2-1) 7% 2-BB(3F)B-3 (3-3) 5%V2-BB(3F)B-1 (3-3) 5% 3-HB(2F,3F)-O2 (4-1) 5% 5-HB(2F,3F)-O2 (4-1) 5%3-HHB(2F,3F)-O2 (4-2) 5% 5-HHB(2F,3F)-O2 (4-2) 5%NI=91.8° C.; Tc≦−20° C.; Δn=0.109; Δ∈=−3.5; η=19.0 mPa·s

Example 15

1V2-HB(2F,3F)-O2 (1-1-1) 8% 1V2-HB(2F,3F)-O3 (1-1-1) 8% 1V2-HB(2F,3F)-O4(1-1-1) 8% 1V2-HHB(2F,3F)-O2 (1-2-1-1) 5% 1V2-HHB(2F,3F)-O3 (1-2-1-1) 5%1V2-HBB(2F,3F)-O2 (1-2-1-2) 5% 3-HH-V (2-1) 17% 3-HH-V1 (2-1) 10%V-HHB-1 (3-1) 5% 3-HBB-2 (3-2) 3% 1V-HBB-2 (3-2) 3% 3-HB(2F,3F)-O2 (4-1)6% 5-HB(2F,3F)-O2 (4-1) 6% 5-HHB(2F,3F)-O2 (4-2) 6% 2-HBB(2F,3F)-O2(4-3) 5%NI=78.7° C.; Tc≦−20° C.; Δn=0.098; Δ∈=−3.4; η=18.8 mPa·s

Example 16

1V2-HB(2F,3F)-O2 (1-1-1) 14% 1V2-HB(2F,3F)-O3 (1-1-1) 14%1V2-HB(2F,3F)-O4 (1-1-1) 12% 1V2-HHB(2F,3F)-O2 (1-2-1-1) 7%1V2-HBB(2F,3F)-O2 (1-2-1-2) 5% 1V2-HH2B(2F,3F)-O2 (1-2-2-1) 5% 2-HH-3(2-1) 10% 3-HH-5 (2-1) 5% 3-HH-V (2-1) 10% 3-HH-V1 (2-1) 9% 3-HHB-1(3-1) 3% 3-HHEBH-5 (3-6) 3% 1O1-HBBH-3 (—) 3%NI=77.6° C.; Tc≦−20° C.; Δn=0.088; Δ∈=−3.4; η=17.2 mPa·s

INDUSTRIAL APPLICABILITY

The liquid crystal composition of the invention can be used in an AMdevice having a short response time, a large voltage holding ratio, alarge contrast ratio, a long service life and so forth, for example, aliquid crystal projector, a liquid crystal television and so forth.

1. A liquid crystal composition having a negative dielectric anisotropycomprising a first component comprising at least one compound selectedfrom the group of compounds represented by formulas (1-1) and (1-2), anda second component comprising at least one compound selected from thegroup of compounds represented by formula (2):

(in formulas (1-1), (1-2) and (2), R¹ is independently alkyl having 1 to12 carbons; R², R³ and R⁴ are each independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12carbons; Z¹, Z² and Z³ are each independently a single bond or —(CH₂)₂—;and ring A is 1,4-cyclohexylene or 1,4-phenylene.)
 2. A liquid crystalcomposition having a negative dielectric anisotropy comprising a firstcomponent comprising at least one compound selected from the group ofcompounds represented by formulas (1-1-1) and (1-2-1), and a secondcomponent comprising at least one compound selected from the group ofcompounds represented by formula (2-1):

(in formulas (1-1-1), (1-2-1) and (2-1), R¹ is independently alkylhaving 1 to 12 carbons; R², R³ and R⁴ are each independently alkylhaving 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having2 to 12 carbons; and ring A is 1,4-cyclohexylene or 1,4-phenylene.) 3.The liquid crystal composition according to claim 1, wherein the firstcomponent is at least one compound selected from the group of compoundsrepresented by formula (1-1), and the second component is at least onecompound selected from the group of compounds represented by formula(2).
 4. The liquid crystal composition according to claim 1, wherein thefirst component is at least one compound selected from the group ofcompounds represented by formula (1-2), and the second component is atleast one compound selected from the group of compounds represented byformula (2).
 5. The liquid crystal composition according to claim 1,wherein a ratio of the first component is from 30% by weight to 80% byweight, and a ratio of the second component is from 20% by weight to 70%by weight, based on the total weight of the liquid crystal composition.6. The liquid crystal composition according to claim 1, wherein thecomposition further comprises, in addition to the first component andthe second component, at least one compound selected from the group ofcompounds represented by formula (3) as a third component:

(in formula (3), R⁵ and R⁶ are each independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12carbons; Ring B, ring C, ring D and ring E are each independently1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or3-fluoro-1,4-phenylene; Z⁴ and Z⁵ are each independently a single bond,—(CH₂)₂—, —CH₂O—, —OCH₂—, —COO— or —OCO—; and P is 0 or 1.)
 7. Theliquid crystal composition according to claim 6, wherein the thirdcomponent is at least one compound selected from the group of compoundsrepresented by formulas (3-1) to (3-4):

(in formulas (3-1) to (3-4), R⁷ is independently alkyl having 1 to 12carbons or alkenyl having 2 to 12 carbons; and R⁸ is independently alkylhaving 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having2 to 12 carbons.)
 8. The liquid crystal composition according to claim6, wherein the third component is at least one compound selected fromthe group of compounds represented by formulas (3-5) to (3-7):

(in formulas (3-5) to (3-7), R⁷ is independently alkyl having 1 to 12carbons or alkenyl having 2 to 12 carbons; and R⁸ is independently alkylhaving 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having2 to 12 carbons.)
 9. The liquid crystal composition according to claim7, wherein the third component is at least one compound selected fromthe group of compounds represented by formula (3-1).
 10. The liquidcrystal composition according to claim 8, wherein the third component isat least one compound selected from the group of compounds representedby formulas (3-6) and (3-7).
 11. The liquid crystal compositionaccording to claim 6, wherein a ratio of the first component is from 30%by weight to 75% by weight, a ratio of the second component is from 20%by weight to 65% by weight, and a ratio of the third component is from5% by weight to 50% by weight, based on the total weight of the liquidcrystal composition.
 12. The liquid crystal composition according toclaim 6, wherein the composition further comprises, in addition to thefirst component, the second component and the third component, at leastone compound selected from the group of compounds represented byformulas (4-1) to (4-4) as a fourth component:

(in formulas (4-1) to (4-4), R⁹ is independently alkyl having 1 to 12carbons; and R¹⁰ is independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons or alkenyl having 2 to 12 carbons.)
 13. Theliquid crystal composition according to claim 12, wherein the firstcomponent is at least one compound selected from the group of compoundsrepresented by formulas (1-1-1) and (1-2-1), the second component is atleast one compound selected from the group of compounds represented byformula (2-1), the third component is at least one compound selectedfrom the group of compounds represented by formulas (3-1), (3-5) and(3-6), and the fourth component is at least one compound selected fromthe group of compounds represented by formulas (4-1) to (4-3).
 14. Theliquid crystal composition according to claim 12, wherein a ratio of thefirst component is from 30% by weight to 70% by weight, a ratio of thesecond component is from 20% by weight to 60% by weight, a ratio of thethird component is from 5% by weight to 45% by weight, and a ratio ofthe fourth component is from 5% by weight to 45% by weight, based on thetotal weight of the liquid crystal composition.
 15. The liquid crystalcomposition according to claim 1, wherein the composition has an opticalanisotropy of from 0.07 to 0.20.
 16. The liquid crystal compositionaccording to claim 1, wherein the composition has a dielectricanisotropy of from −5.0 to −2.0.
 17. A liquid crystal display devicethat includes the liquid crystal composition according to claim
 1. 18.The liquid crystal display device according to claim 17, wherein theliquid crystal display device has an operation mode of a VA mode or anIPS mode, and has a driving mode of an active matrix mode.